#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/11/16 11:09
# @Author  : LuChao
# @Site    :
# @File    : 4.py
# @Software: PyCharm

n=0
s=0
t=1
for n in range(1,21):
    t*=n
    print("T的值为 %d N的值为%d"%(t,n))
s+=t
print(s)
